Spatial variability of aquifer properties affects the movement and spread of contaminants in the subsurface. Since a complete spatial representation of the heterogeneous aquifer properties cannot be obtained, predictions of solute movement through porous media contain uncertainty. An understanding of the spatial variability of aquifer properties and their effects on flow and transport is essential for making reliable predictions of solute transport, a necessary component of optimal design of remediation systems, risk assessment, siting of water supply wells, and others.
Aquifer heterogeneity occurs at multiple scales; however, measurements of aquifer properties are often made at only a limited number of scales. These measurement scales may not correspond to the scales that control subsurface flow and transport. In this study, we will analyze dominant scales of aquifer properties that affect groundwater flow and solute transport and identify relationships between dominant scales and physical and chemical heterogeneity of aquifer properties. Continuous wavelet transforms (CWT) will be used to extract scale information from data sets of the spatial distribution of aquifer properties and system states (hydraulic head and solute concentration). The CWT is a tool that extracts local information at multiple scales. The technique will be developed and tested using synthetic data sets and numerical simulations. It will subsequently be used with data from laboratory- and field-scale flow and transport experiments to identify dominant scales of aquifer properties; the evolution of dominant scales of system states; and the relationships between dominant scales, the degree of heterogeneity, and the effects on solute transport. Knowledge of the dominant scales of flow and transport and the relationship between them and aquifer heterogeneity will facilitate more targeted sampling for aquifer characterization and improved predictions of subsurface flow and transport.
The educational goals are to teach students to recognize variability and uncertainty in physical systems and to perform engineering design and analysis that accounts for this uncertainty; to improve science and engineering education by emphasizing the practical applications of engineering and science knowledge; and to encourage women and underrepresented minorities to consider technical fields. They will be achieved through exposure to realistic, complex data sets for analysis and design; practical hands-on activities to accompany lectures; and outreach activities to promote science and engineering fields to underrepresented minorities and women.
